German Continental Deep Drilling Programme

During 1987 to 1995 (one of) earths deepest boreholes. Indoor and outdoor museum/exhibition, including some background on deep drilling and geoscience.

Kids/Teen-friendly.

Easily possible to spend a few hours there. Café may be closed during off-season.

[1] https://en.wikipedia.org/wiki/German_Continental_Deep_Drilling_Programme